This study will address two major issues that need to be resolved to determine whether it is now feasible to pursue a multi-site evaluation of the clinical effectiveness of EMS Systems. The first issue involves developing a means for classifying the level of development of existing EMS systems. The second issue involves assessing the feasibility of collecting the types of patient-specific data that can be used to test the clinical effectiveness of EMS systems. The following questions will be addressed: 1) is the EMS program ready for outcome evaluation; i.e., are there really examples from the population of 265 federally funded EMS systems that have achieved the status of fully developed systems and would, consequently, be ready for evaluation; 2) can an evaluation of the EMS program be performed with anything resembling a rigorous quasi-experimental design; 3) will the patient data essential for outcome evaluation be available and accessible in the complex EMS environment. The methodological approach for this project is basically descriptive with an emphasis on assessing the feasibility of techniques and procedures for systematic data collection. This will require on-site field work and data collection in two sites following a schedule of carefully designed activities and techniques. The development of criteria or indicators of EMS system development and the specification of discrete levels or stages of developement will preceed site selection. Both system-wide and patient-specific data will be collected in a manner allowing for self-evaluation and adjustment. Data collection efforts at one site will be analyzed and evaluated prior to preceeding to the second site.